Modern blast furnaces usually have several tapholes. Each of these taholes is served by its own drilling machine. As an efficient taphole drilling machine is relatively expensive, it would, of course, be interesting for cost reasons to develop a machine which can be used for several adjacent tapholes at the same time.
A taphole drilling machine of this type was already described in DE-A-19 62 953 in 1967. This machine comprises a fixed bracket and an arm, the first end of which can be swivelled about a first axis and is mounted in the fixed bracket. The arm, which can be swivelled by a drive from a first operating position in front of the first taphole into a second operating position in front of the second taphole, carries at its free end a vertical pivot on which a mount is mounted. A control rod is connected by swivel joints to a fixed lever arm on the bracket and to a crank firmly seated on the pivot. These form a four-link swivel joint mechanism, in which a swivelling movement of the arm about the first axis produces a swivelling movement of the mount about the second axis. To allow adaptation of the angle of inclination of the drilling axis to the respective taphole, the mount is connected by a horizontal swivelling joint to vertical pivots, and a tilting cylinder is arranged between the mount and a flange secured rigidly to the vertical pivot. To adapt the height of the drilling axis to the respective taphole on the other hand it is proposed that the mount be brought to different points of proximity to the taphole, i.e. to limit the swivelling movement of the arm. However, the result is that only very small differences in height can be compensated, because firstly the swivelling movement of the arm determines the final position of the mount and, secondly, the distance between the mount end and the taphole should preferably be identical.
A rock drilling machine, as used in mines, for example, is known from U.S. Pat. No. 3,349,975. This rock drilling machine has a parallelogram mechanism with a frame, three links and four joints, which permits parallel displacement of a drill mount by means of a first pressure cylinder. A second pressure cylinder is connected between the parallelogram mechanism and the drill mount and permits tilting of the drill mount. An additional rotary motor permits 360.degree. rotation of the parallelogram mechanism about a horizontal axis. The aim of the device is to permit universal alignment of the drill mount via a hydraulic control system in relation to a horizontal axis, so that the rock drilling machine can drill several holes without having to be repositioned.
A taphole plugging machine, in which a mud gun is suspended by two articulated supporting links from a supporting structure, is known from FR-A-2 604 511. A pressure cylinder permits swivelling of the mud gun in a vertical plane and thus firm contact with its nozzle against the taphole. One of the two supporting links is longitudinally adjustable, so that the inclination of the mud gun can be adapted to the inclination of a taphole.
There is a need for a taphole drilling machine which permits variation in the height and inclination of the drilling machine to serve two tapholes, which can approach two tapholes with a different height and inclination in an optimum manner.